The present invention relates to photographic copying or printing machines of the type provided with exchangeable format masks for originals of differing format, the format masks and the originals masked by them being brought by a carrier structure into and then out of the copying station of the machine.
In photographic copying machines, it is known to provide a set of differing exchangeable original holders, in order to be able to copy originals of differing formats, or to produce from originals which are all of the same format enlarged copies of different portions of the originals. If it also known to lay originals to be copied on a rotary or slidable infeed table; in this way an original which has already been copied can be manually removed from one end of the table and replaced by another, while another original at the other end of the table is located at the copying station and being copied. Then the table is rotated or shifted, and the just copied original is moved to the change station where it can be replaced by another, whereas the original just laid onto the table at the change station moves to the copy station.
The disadvantage of this type of infeed system is that, when changing over to the next original at the change station, vibrations and the like, resulting from the operator removing an already copied original and laying down a yet to be copied original at the change station, can be transmitted via the infeed table to the original presently located and being copied at the copying station. Understandably, this leads to loss of image sharpness in the copies produced, especially in copying machines set up to produce enlargements having a width of up to 30 cm and more.